<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>计算圆的面积和周长</title>
</head>

<body>
    <script>
        function getArea(r) {
            var area = r * r * Math.PI;
            return area;
        }

        function getLong(r) {
            var long = 2 * Math.PI * r;
            return long;
        }
        console.log('半径为5的圆的面积是：' + getArea(5))
        console.log('半径为5的圆的周长是：' + getLong(5))
    </script>
</body>

</html>